Quadratic Numbers

Quadratic Equations

Equation for formula of all quadratic numbers: An2 + Bn + C

For example:
Sequence:3 7 13 21 31 43 57 73
1st Order: 4 6 8 10 12 14 16
2nd Order: 2 2 2 2 2 2

If n=1,
A + B + C = 3
3A + B (first difference) = 4
2A (second difference) = 2

So,
A= 1 because 2A= 2
B= 1 because 3A+B= 4
C= 1 because A(1) + B(1) + C= 3

Formula n2 + n + 1
Test: 2*2 + 2 + 1= 7